In the medical field, optical analysis systems and optical methods are used to optically analyze organic dispersions, which consist, on the one hand, of a dispersion medium and, on the other hand, of a dispersed phase. The dispersed phase generally comprises particles, in particular organic material, for example, cells or cell components. The dispersion medium can be understood as media which comprise the dispersed phase, dilute it, or receive it in another manner, for example, blood plasma.
The analysis of the components of a dispersion can be carried out using optical methods, wherein a light beam, in particular a laser beam, is focused in the dispersion and subsequently examined for various optical features. In this manner, measured values for specific features of the dispersion can be ascertained.
An analysis system is known from WO 00/58727, which consists of a light source, the light of which is focused in a dispersion circulation unit (flow cell) and is subsequently analyzed. The analysis relates in particular to the spectral ascertainment of the wavelengths of the light used which are absorbed in the dispersion. On the other hand, the diffraction characteristics in the near field and the far field are documented, to infer specific properties of the dispersion, in particular the particles contained in the dispersion, for example, the red blood cells, the white blood cells, or blood platelets. An optical, hematological examination, as is known from the prior art, can advantageously be performed in an automated manner, wherein an array of optical features of the dispersion are examined. However, the optical analysis method limits the information content which is extractable for the dispersion. Although items of information can be obtained on the absorption behavior or frequency values of white and red blood cells or blood platelets, the extracted information content is still inadequate for carrying out many medical diagnoses.
For example, in the case of the malaria diagnosis, a blood sample of the patient cannot be automatically examined as a dispersion, but rather must be examined manually under the microscope in the laboratory. The present best method (the gold standard) for the malaria diagnosis is the blood smear on a slide or between two slides. Malaria parasites are detected by light microscopy by means of thin and thick blood smears. The accuracy of the diagnosis is dependent to a large extent on the quality of the blood smear and the experience of the laboratory personnel.
A special ring shape, which can be recognized under the microscope, is characteristic for red blood cells infected by parasites, however, a reliable diagnosis is only ensured if a sufficient number of these ring-shaped red blood cells can be counted in the dispersion of the blood sample. On the basis of this counting experiment, a physician can recognize whether it is a severe or less severe malaria infection. Unfortunately, counting the ring-shaped red blood cells under the microscope is very boring, cumbersome, and subject to error, so that a malaria diagnosis is costly and excessively inaccurate. In addition, various laboratories refer in various notations to different ranges with respect to the counted ring-shaped red blood cells. In this manner, the question also arises of how a standardized, dependable malaria diagnosis or also diagnoses of other illnesses or negative states can be carried out reliably.